Implement weight transfer with feedback control

ABSTRACT

An implement weight transfer system having a feedback control system to vary the amount of weight transfer as product stored on the implement is used.

FIELD

This disclosure relates to implements, such as agricultural implements,having a frame with multiple sections and in particular to a weighttransfer system to transfer weight from one frame section to another.

SUMMARY

An implement weight transfer system is described having a feed backcontrol system to vary the amount of weight transfer as product storedon the implement is consumed during operation of the implement.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of an agricultural implement, namely a row cropplanter;

FIG. 2 is a perspective view of a wheel assembly of the implement ofFIG. 1;

FIG. 3 is a side elevational view of a ground engaging tool of theimplement of FIG. 1;

FIG. 4 is front view of a portion of the tool bar of the implement ofFIG. 1;

FIG. 5 is a hydraulic schematic for the weight transfer system on theimplement of FIG. 1; and

FIG. 6 is a schematic diagram of an example control system for theweight transfer system.

DETAILED DESCRIPTION

An implement 10 is shown in FIG. 1 as a row crop planter. Implement 10has a frame 12 which includes a draw bar 14 and a tool bar 16. At theforward end of the draw bar is a tongue 18 for coupling the frame 12 toa towing vehicle such as a tractor (not shown). The tool bar has a mainframe section 20 and left and right frame wing sections 22 and 24extending laterally from the frame main section. The frame wing sectionsare pivotally coupled to the frame main section for rotation about foreand aft extending axes 36 and 38. The pivotal connection allows the wingsections to follow the ground contour as the machine moves through afield. Row units 26 are carried by the main frame section 20 and serveas main section ground engaging tools. Row units 28 are carried by theframe wing sections and form wing ground engaging tools. Generallyspeaking, the row units 26 and 28 are all identical but need not beidentical. The row units will be described in more detail below.

A product storage system 40 is mounted to the frame main section andincludes product bins or tanks, 42, 44 and 46. The bins hold seed thatis delivered pneumatically to mini-hoppers on the row units. In otherembodiments (not shown), the bins may hold dry or liquid fertilizer orwater that used to dilute a concentrated insecticide or other chemicalto be applied.

Main wheel assemblies 30 are coupled to the frame main section tosupport the frame main section for movement over a ground surface. Wingwheel assemblies 32 are coupled to the frame wing sections forsupporting the frame wing sections for movement over a ground surface.Two wing wheel assemblies 32 are shown in FIG. 2. Each wing wheelassembly 32 includes a tire and wheel 50 mounted to a support structure52 for rotation on an axle 54. The support structure includes a mountingbracket 56 secured to the frame wing section 24 and a lift arm 58. Thelift arm is pivotally connected to the bracket 56 by a pin 60. The framewing section 24 can be raised or lowered by operation of hydrauliccylinders 62 coupled between the lift arms 58 and mounting brackets 56which are in turn secured to the frame wing section 24. Both the rod endand the base end of each cylinder 62 are attached to the lift arms andbrackets by pins 64. The main wheel assemblies 30 have similarcomponents as the wing wheel assemblies 32, namely wheels and tires,lift arms and hydraulic cylinders. The main wheel assemblies willtypically have components sized to carry larger loads than the wingwheel assemblies.

With reference to FIG. 3, a row unit 28 is shown in greater detail. Rowunit 28 includes a row unit frame 120 which is attached to the framewing section 24 by parallel linkage 122. Linkage 122 permits up and downmovement of the row unit relative to the tool bar or frame wing section24 to follow ground contours. Row unit frame 120 carries a double discfurrow opener 124 for forming a seed furrow 126 in soil or ground 127.Gauge wheels 128 are provided on the sides of the two opener discs. Thegauge wheels function as furrow depth regulation members. Each gaugewheel is respectively associated with one disc of double disc furrowopener 124. More particularly, each gauge wheel 128 is positionedslightly behind and immediately adjacent to the outside of eachrespective disc of double disc furrow opener 124. (The gauge wheels canbe placed in other locations relative to the opener discs if desired.)The gauge wheels 128 are vertically adjustable relative to the openerdiscs to vary the depth of the furrow 126 which is cut into the soil bythe double disc furrow opener 124. Adjustment link 148, pivotallymounted to the frame at pivot pin 146 locks into place and bears againstthe top of pivot arms 150 carrying the gauge wheels. The adjustment link148 thus limits upward movement of the gauge wheels relative to theopener discs.

A seed meter 132 is also carried by row unit frame 120. Seed meter 132receives seed from a mini seed hopper 134. Seed is delivered to themini-hoppers from the product storage system 40 by a commonly knownpneumatic distribution system, an example of which is shown in U.S. Pat.No. 6,688,244 and incorporated herein by reference. The seed meter driveis not shown; numerous types of drive mechanisms are well known. Seedmeter 132 delivers seeds sequentially to a seed tube 136 through whichthe seed falls by gravity to the furrow 126. The seed meter 132 and seedtube 136 form a product dispenser to dispense product to the furrow 126.A seed sensor 138 on the seed tube 136 detects passing seed as part of amonitoring system. The seed sensor and monitor 230 can detect theproduct being dispensed. By combining the detected product dispensedwith machine travel speed or position and time data, a product dispenserate is determined.

A pair of closing wheels 142 follows behind the gauge wheels and arepositioned generally in line with double disc furrow opener 124. Closingwheels 142 push soil back into the furrow 126 upon the seed or productdeposited therein. Numerous types and styles of closing wheels ordevices are known.

A supplemental down force system includes a row unit down force actuator140 in the form of an adjustable pneumatic down force cylinder 144 oneach row unit 28. The cylinder 144 acts between the tool bar 16 and thelinkage 122 to apply supplemental down force on the row unit and the rowunit components engaging the soil. The supplemental down force appliedby the cylinder 144 ensures that there is sufficient force to fullyinsert the double disc furrow opener 124 into the soil, forming thefurrow 126 to the desired depth. The supplemental down force applied tothe row unit by the cylinder is shown by the arrow F_(D). While only adown force cylinder is shown in FIG. 3, there may also be an up force,or lift cylinder. In other systems, there may be an adjustablemechanical spring providing a supplemental down force together with apneumatic lift cylinder to fine tune the total down force. In such asystem, the spring would be set to provide a down force that is greaterthan what is needed at any time and the lift cylinder would becontrolled to counter-act a portion of the spring down force to producea desire net down force on the row unit.

The row unit weight also produces a down force shown by the arrow F_(G)acting through the center of gravity of the row unit. These two downwardacting forces, F_(D) and F_(G) are counter-acted by upward forces actingon the row unit. The opener penetrates the soil and has a force F_(O)acting upward on the opener. When the opener 124 is fully penetrating,the gauge wheels 128 will be in contact with the soil and a soilreaction force F_(R) acts upward on the gauge wheels. An additionalupward force on the row unit is the force F_(C) acting on the closingwheels 142. Other attachments to the row unit, not shown, such as acoulter or row cleaner will also generate an upward force on the rowunit. In systems with an up force cylinder 80, the supplemental downforce F_(D), may at times be positive and at times negative, meaning itmay be directed downward or upward, but is referred to herein as a “downforce” regardless of direction.

A minimum soil reaction force F_(R) acting on the gauge wheels 128 isdesired to have confidence that the opener is fully penetrating the soilto the desired depth. If the soil reaction force F_(R) acting on thegauge wheel is zero, the gauge wheel is not touching the soil. This onlyoccurs when the opener is not fully penetrating the soil to the desireddepth. Thus, some level of soil reaction force F_(R) greater than zerois desired to be maintained to ensure there is full penetration by theopener. The magnitude of the force F_(R) is measured by a sensor or loadcell which can be placed in a variety of locations on the row unit. Oneexample is a load sensor pin 146 in the gauge wheel depth adjustmentlink 148. Adjustment link 148 bears against and resists upward movementof the pivot arm 150 carrying the gauge wheels 128. A suitable loadsensor pin is shown in US2010/0180695 A1 incorporated herein byreference. The load measured at the pin 146 is proportional to the soilreaction force F_(R), thus allowing the controller 82 to determine thesoil reaction force from the measured load. Load sensing pins may beprovided at other points in the gauge wheel mounting and adjustmentstructure. Each row unit may be equipped with a gauge wheel load sensorpin or only select row units may be so equipped. If only a few row unitshave gauge wheel load sensors, it is desired that there be at least onerow unit on the frame main section and on row unit on each frame wingsection with a gauge wheel load sensor.

The row units 26, 28 are representative of row crop planter row unitsfor planting seed. The implement 10 may have other types of seedplanting row units or may only be for applying fertilizer or chemicals.Each opener will need to have sufficient down force to ensure the openeris fully penetrating the soil.

When the bins 42, 44, 46 are full, the weight on the frame main sectionand thus the main wheel assemblies is greater than the weight on thewing wheel assemblies. The greater weight on the main wheel assembliescan lead to increased soil compaction in the tire tracks of the mainwheel assemblies 30 compared to the soil compaction caused by the wingwheel assemblies 32 and certainly more compaction than there is betweenrow units where there are no wheel assemblies. Depending on the soiltype and conditions, this increased compaction can result in lower yieldfrom the rows adjacent the main wheel assemblies. To alleviate theeffects of soil compaction, the machine is equipped with a weighttransfer system to transfer weight from the frame main section to theframe wing sections. This spreads the weight of the implement over allthe wheel assemblies to achieve a greater balance of loads on the wheelassemblies. Equal load on all wheel assemblies is not necessarily thegoal as the main wheel assemblies may be larger than the wing wheelassemblies and able to carry a greater total load while producing thesame soil compaction. As such, the goal is to achieve more load balanceacross the machine than if there is no weight transfer to reduce soilcompaction caused by the main wheel assemblies.

The weight transfer system includes a hydraulic cylinder 70 connectedbetween the main frame section 20 and each wing section 22, 24 spanningacross the wing pivot axes 36 and 38. The right cylinder 70 is shown inFIG. 4 spanning across the pivot axis 38. When the cylinder rod isextended, the cylinder creates a clockwise moment about the axis 38 asviewed in FIG. 4. This creates a greater up-force, or soil reactionforce, on the wing wheel assemblies 32 and a corresponding decrease onthe up-force on the main wheel assemblies 30. The cylinder 70 could bemounted beneath the frame; in which case the rod is retracted to causethe weight transfer. Weight transfer of this type is known and is usedon the John Deere 1720 stack-fold planter and the Kinze 3600 series and4900 series planters. These planters, however, have no means to controlthe weight transfer to ensure that the loads are more balanced acrossthe implement wheel assemblies. The amount of weight transfer ismanually determined by operator input and remains at a set amount untilchanged by the operator.

To provide for greater load balance across the implement, the wheelassemblies can be provided with load cells to measure the load on thetires and wheels 50. The wheel assembly loads can be determined by aload cell at the axles 54, the pins 60 attaching the lift arms to themounting brackets 56 or the pins 64 at either end of the cylinders 62.Suitable load sensing pins, bolts, etc. are available from Strainsert,Inc. of Conshohocken, Pa. The pressure in the wheel lift cylinders 62can also be used to determine the load on the wheel assembly. A weighttransfer control system operates the cylinders 70 to provide weighttransfer to achieve greater balance of the soil reaction forces on thewheel assemblies. Only one wheel assembly on the frame main section andone wheel assembly on each frame wing section need to be equipped with aload cell to operate the cylinders 70 for weight transfer. However, allwheel assemblies can be so equipped if desired.

During operation of the machine, the product in the bins will graduallybe applied to the soil or to plants, etc. and the weight on the mainwheel assemblies will be reduced. The weight transfer control systemwill continually monitor the load on the wheel assemblies and adjust theamount of weigh transfer to maintain the improved load balance. Thecontinuous monitoring of the wheel assembly loads enables feed back tothe control system to make continuous adjustments in the magnitude ofweight transfer.

The weight transfer can be controlled individually to the left and rightwing sections to take into consideration weight differences between thetwo wings sections. For instance, if the machine is equipped withextendable row markers, the wing section with the row marker extendedand in the ground will have a lower weight than the other wing sectionwhere the row marker is not extended.

The hydraulic system 220 for the weight transfer is shown in FIG. 5.Valve 222 controls the flow of oil into and out of the cylinders 70.When the pressure in the cylinder reaches the desired level, the valvecloses, trapping the oil in the cylinder and maintaining the down forceon the wing section. The valve 222 is a proportional electronicreducing/relieving valve. The valve pressure is variable and set by a DCcurrent input. This input is varied by the weight transfer controlsystem to produce the desired pressure in the cylinders 70. As notedpreviously, the wing section is adapted to float on the ground. If thewing section travels over a low point, the pressure in the cylinder 70will force the wing section downward to follow the ground, dropping thepressure in the cylinders 70, causing the valve 222 to open and supplymore oil to the cylinders. If the wing section travels over a raisedterrace, the pressure in the cylinder 70 will increase, causing thevalve 222 to open and relieve pressure enabling the wing section tofloat upward. Alternatively, the hydraulic system can employ anaccumulator with pressure to act as a spring allowing the wing sectionto float continuously. While a single valve 222 is used to control boththe left and right wing weight transfer cylinders 70, separate valves222 can be provided to separately control weight transfer to each wingsection.

In place of actual measurement of the wheel assembly loading, othermeans can be used to approximate the wheel loading. For example, thebins 42, 44, 46 may be mounted on load cells to measure the weight ofproduct in the bins. Suitable load cells are commercially available fromDigi-Star Holdings, Inc. of Fort Atkinson, Wis. The weight transfercontroller can determine the pressure needed in the cylinder 70 totransfer sufficient weight to substantially balance, or improve thebalance of the loads on the wheel assemblies based on the machinegeometry and the measured weight of product in the bins.

Bin level sensors can be used in place of bin load cells to determinethe quantity of product in the bins. The product level and either actualdensity information input into the controller or an estimated densityinput can be used to determine the bin weight to use in calculating acylinder pressure for weight transfer.

Heretofore, the weight transfer system has been described as usingactual measured wheel loads or an approximation based on the weight ofthe product in the bins or an estimated weight of the product based on abin level sensor. The weights or bin levels are continuous inputs to thecontrol system for varying the weight transfer as the product isconsumed. However, the weight transfer system could operate without anyweight measurement or bin level measurement. When the operator fills thebins, he can input into the controller an estimate of the bin filllevel. The product density can also be input to the controller. Thedensity can be from typical density values for various products such asseed corn or bean seed, etc or the product density can be measured bythe operator and input into the controller. The controller can use thisinformation to estimate the product weight and then calculate a desiredpressure in the cylinder 70 to achieve an approximate balance across thewheel assemblies. By then using the seed sensor to count the seedsdispensed, the changing level of product in the bins can be continuouslyestimated. Other product dispensing sensors can be used to measure therate of fertilizer or other chemical application. The calculated changein product in the bins can be used to continuously vary the amount ofweight transfer to the frame wing sections.

In addition to balancing the load on the wheel assemblies across themachine, the weight transfer system can also be used to ensure the wingsections have sufficient weight for the row unit down force system. Ifthe machine is working in hard soil, the static weight of the wingsection may not be great enough for the pneumatic cylinders 144 to applyenough force F_(D) to achieve the desire gauge wheel reaction forceF_(C). In some instances, operators add iron weights to the frame wingsections to enable enough row unit down force. With the weight transfersystem described above, weight can be transferred from the frame mainsection to the frame wing sections for row unit down force even whenweight transfer is not needed to reduce soil compaction. This canobviate the need to add iron weights to the wing sections. The row unitdown force sensors, such as pins 146, can be used to determine the needfor weight transfer for row unit down force. In addition, if the framewing section is too high off the ground as measured by a height sensoror position sensors on the linkage 122 bottoming out, weight can betransferred to the frame wing section to lower its position. This willbe in conjunction with the wing wheel assembly position being in aposition to allow downward movement of the frame wing section.

An example weigh transfer control system 200 is shown in FIG. 6. Thecontrol system includes a controller 202 including a micro-processorprogrammed for the function of controlling the weight transfer system.The controller 202 receives one or more load inputs from the load inputbox 204. As mentioned before, the load inputs can include a main wheelassembly load sensor 206. The load sensor 206 can be a wheel axle 54load cell, or load cell on any of the pins 60 or 64 as described above.A similar wing wheel assembly load sensor 208 can also be provided. Theload on the wheels can also be determined by the internal pressure inthe wheel lift cylinder with a sensor 210. The sensor 210 is likely apart of the hydraulic system. Other load sensors include the bin loadcell 212 and the bin level sensor 214.

The control system 200 also includes a display/user input device 216which may be a touch screen, to allow the operator to manually input abin level estimate as well as input a nominal density value for theproduct. The controller also receives an input of product dispensingfrom the seed sensor 138 and other product dispensing sensors. The seedsensor input will likely be aggregated data from the planter monitor230. The monitor also receives travel speed and/or position and timeinformation from which product dispensing rates can be determined and aproduct dispense rate signal delivered to the weight transfer controller202. The controller 202 uses these inputs to determine the amount ofweight transfer and then sends a command to a hydraulic controller tooperate the weight transfer cylinders 70. The physical architecture ofthe control system may vary from what is shown. For example, thecontroller 202 may be part of another system such as the planter monitoror the hydraulic controller, etc. Likewise, the display 216 may be usedfor other functions as well.

The control system 200 may also have an internal or external memory torecord bin loads and the amount of weight transfer by location in thefield. The location data is collected through a GPS or other positioningsystem now commonly used in precision agriculture. The data regardingbin loads and weight transfer can be used later and correlated withother field operations and subsequent yield data.

In the simplest form, the weight transfer system uses operator providedinformation. When the operator fills a product into the bins, he thenenters into the control system an estimate of how much product is in thebins, for example, to the nearest ⅛ of a bin. The operator also inputsthe density of the product. The density can be from published tables forthe particular product, or nominal values for the class of product.Alternatively, the operator can weigh a given volume of product,calculate the density and input that amount. The controller uses theestimate of bin fill and the density information to determine theproduct weight. This is added to the dead weight of the main section ofthe implement to determine the wheel load. With a known dead weight forthe wings, the controller determines the amount of weight transferneeded to balance the implement load over all the wheel assemblies andthe needed pressure in the weight transfer cylinders 70 to produce thedesired weight transfer. As the implement is operated in the field, thecontroller uses dispense rate information from the seed sensors or otherproduct sensors to determine how the product weight is changing. Otherproduct dispensing systems may be programmed to apply product at acertain rate such as a certain number of gallons of chemical per acre.As the implement moves over the field, that information can be used tocalculate a reduction in the quantity of chemical still in the bins ortanks. The controller uses the product dispensing information tocontinuously change the amount of weight transfer from the frame mainsection to the wings.

Greater precision is available with a measurement of the product in thebins. This can be done by a bin level sensor and user input data of thedensity. The bin level sensor can be used during operation to monitorthe rate of consumption of the product and change the weight transferaccordingly. Still greater precision can be obtained by directly sensingthe weight of the product in the bins or tanks with load cells on eachbin and tank or by measuring the load on a main wheel assembly asdescribed above. The change in this load over time is used to change theweight transfer. The greatest degree of precision is available frommeasuring the main wheel loads and the wing wheel loads. The weighttransfer is then controlled to keep the desired loads on the main wheelassemblies and the wing wheel assemblies.

The implement may be operated in a manner that provides for a fixedportion of the total implement weight to be carried by the frame mainsection and the frame wing sections. For example, it may be desired thatthe frame main section carry 50% of the implement weight while each ofthe right and left frame wing sections carry 25% of the implementweight. After the main wheel assembly loads and the wing wheel assemblyloads are determined, the weight transfer system transfers weight to thewings to achieve the desired weight distribution. During operation, theweight transfer is changed to maintain the desired weight distributionas the product in the product storage system on the frame main sectionis consumed.

The implement has been described in the context of a planter having amain frame section with laterally extending wing sections. The weighttransfer system could also be adopted for use on an implement having afore and aft arranged frame sections where only one frame sectioncarries the load of the product storage system and it is desirable totransfer weight from one section to the other.

Having described the implement and its operation, it will becomeapparent that various modifications can be made without departing fromthe scope of the invention as defined in the accompanying claims.

The invention claimed is:
 1. An implement comprising: a frame having amain section and a wing section pivotally coupled to the main section; amain wheel assembly coupled to the frame main section to support theframe main section for movement over a ground surface; a wing wheelassembly coupled to the frame wing section to support the frame wingsection for movement over a ground surface; a product storage systemmounted to the frame main section to carry a quantity of a product to beapplied as the implement is moved over the ground; a weight transfersystem coupled to the frame main and wing sections adapted to transferweight from the frame main section to the frame wing section to reducethe load carried by the main wheel assembly; and a control systemadapted to operate the weight transfer system, the control systemresponding to a decrease in a quantity of product in the product storagesystem during operation of the implement to reduce the weighttransferred from the frame main section to the frame wing section duringoperation of the implement and wherein the control system includes anoperator input device wherein an operator is able to input informationrelated to the quantity of a product in the product storage system. 2.The implement of claim 1 wherein the control system includes a productsensor detecting dispensing of product and generating a signal relatedto a decrease in the quantity of product in the product storage systemduring operation of the implement.
 3. The implement of claim 1 whereinthe control system includes a bin level sensor adapted to produce asignal indicating the quantity of product in the product storage system.